2 people are asked (indepently of one another) to choose 2 letters (each) from the letters of the word FRACTION.
Find the probability that: (i) They have no letters in common
(ii) They both choose the same pair of letters.

Ans 15/28
1/28

please explain :-)

Dec 7th 2012, 06:45 AM

Plato

Re: Propability question help please! cheers! :-)

Quote:

Originally Posted by aimsywamesy

2 people are asked (indepently of one another) to choose 2 letters (each) from the letters of the word FRACTION.
Find the probability that: (i) They have no letters in common
(ii) They both choose the same pair of letters.
Ans 15/28 & 1/28

There are $\displaystyle \binom{8}{2}$ to choose two letters.

Thus, there are $\displaystyle \binom{8}{2}$ for the first to pick and $\displaystyle \binom{6}{2}$ for the second to pick totally different letters.